1. Field of the Invention
The present invention relates to a nonaqueous electrolyte secondary battery which exhibits a high rate dischargeability as a driving power supply for electronic apparatuses or a battery for electric vehicles.
2. Description of the Related Art
A nonaqueous electrolyte secondary battery for an apparatus which requires a high rate dischargeability such as motor-driven apparatus, portable electronic apparatus and electric car comprises an electrolyte having a drastically higher resistivity than that of an aqueous electrolyte. Thus it needs to have an increased electrode plate area and an increased opposing area of the electrode plate. To this end, the electrode plate comprises as a substrate a metal foil having a thickness of from 5 to 50 .mu.m and a positive or negative active electrode material applied thereto. As the power-generating element to be incorporated in the battery, there is used one assembled by winding or laminating thin belt-like positive electrodes or negative electrodes with a separator provided interposed therebetween.
The provision of a current-collecting arrangement in a power-generating element has heretofore been accomplished by connecting a collector terminal 2 to an electrode plate at a portion 4 (uncoated portion 4) which is not coated with an active material so that the substrate of the electrode plate is exposed as shown in FIG. 1. However, a battery for electric vehicle or the like must exhibit a high rate dischargeability and thus needs to have a reduced internal resistivity and a uniformalized current distribution. To this end, as shown in FIG. 2, the provision of a current-collecting arrangement in a power-generating element has been accomplished by connecting a plurality of terminals 2 to an electrode plate at an uncoated portion 4 on a longitudinal side edge thereof (multi-terminal collector system).
A nonaqueous electrolyte secondary battery which must exhibit a high rate dischargeability requires a large number of current-collecting terminals. For example, a battery of 100 to 400 Wh class, if structured in a multi-terminal collector system, requires from 10 to 50 terminals and thus faces a great disadvantage that it can be produced at only a reduced efficiency.